Additional Information (Schedule of Valuation and Qualifying Accounts) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Discounts [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	$ 0	$ 0	$ 0
Charged to costs and expenses	604	620	626
Deductions	(604)	(620)	(626)
Balance at end of year	0	0	0
Returned Goods [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	32	40	49
Charged to costs and expenses	127	97	130
Deductions	(127)	(105)	(139)
Balance at end of year	32	32	40
Allowance for Losses on Finance Assets [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	19	23	32
Decrease to allowance	0	(4)	(9)
Balance at end of year	$ 19	$ 19	$ 23